Brian,,, while I was in Houston a while back I picked up a Makita electric die grinder but it did not have a variable speed... but you probably could make it variable with a sewing machine foot throttle..... or Makita probably makes one that is variable speed.... it really helps to cut the speed down some because it seems that the carbide burrs cut better , faster, and smoother in the cast iron if the speed is dropped some....I am sure there are other brands out there... but I dont know them at this time....
On my intake I have to ports in the back behind the carb they had plastic bolts in them. I swapped them out to XRP ones they are 1/8 size on Docs manifold i don't see them anyone know what they are for ?
Without a picture , it is difficult to tell,,,:Brow: but I think you are actually talking about holes that are tapped by the factory for vacume fittings.... they are not bolt holes.... one is for the trans modulator vacume and the other is for the power brake vacume on some models....or on some models the dist. vac advance.... that is the only other holes that I have ever seen in a nailhead intake manifold for sure,, cant remember for the BBB....or the sbb....ou:
makes sense so its a later model nailhead intake I have ? ill get pics tomorrow. man the guy who installed my 4 barrel did some odd stuff.
In a race car only,,, not on the street.... I tried it and the car did not run near as good on the street... runs much better with the heat in....
I'm curious. i did the dual plane mod and header extensions i gained .4 and 3 mph. but i didn't port match the runners. my heads aren't port matched so would i get air reversion if the posts on the intake are bigger than the head?
Lonnie,,, you would get a disturbance of the flow alright ,,,with the air coming in from the carb to the intake , then to the head, at each junction the opening needs to get slightly bigger on the bottom side.... if only a few thousanths of a inch... that way the flow is ever ''expanding'' which is what you need to vaporize fuel... If the air is coming down a runner and suddenly gets to a place that is sharply smaller, that creates a ''eddy'' in the flow and restricts the volume some amount....
You got cool air coming in???? that is worth 8% of the total hp out put....:Brow:It is really strange,,, cool air coming in at the air cleaner,,, and heat in the intake manifold to make the fuel flash into a vapor, makes the engine run best of all on the street.... a nailhead intake is what was called a ''divorced'' intake,,, that is the intake is not part of the engine block,,, it bolts to the heads only... so it runs real cool anyhow... 127 deg. on a fully warmed up engine... so it needs the heat to get mileage and throttle response.... I tried it without the heat and it ran like a 1 legged dog...
I run with the hood off. that's worth .2 in the quarter. no doubt mph would go up with cold air and hood on though. hey can you pm me your number again. i lost it. my buddy acquired a 64 electra with nail head and might need some wisdom when i check it out.
Yep,,,Stu,,,, take a look at Big Pig's post in Da nailhead section,,, Yesterday.... even got pictures.....
I have a quick question about the DDP! Doc, you said that you ran your original AFB and noticed significant improvement. With the AFB, are you running your heatshield and a gasket?
Doc i know it's not strictly related to manifold but You said that those round dimples in intake(in heads) runners shouldn't be removed. I can understand that they control flow somehow but what about dimples in exhaust ports? Do they control flow?? For me they looks like some sort of leftovers from casting process? Maybe there was parafin sticks wich was connecting runners with shell in the mold? In intake runners some of those are merely visible and some are sharp. I am confused on this. Peace Kacper
I hear ya. Kac,,,, I have removed the dimples on some manifolds and left them on some others.... I read in several articles that they were intentially put in by buick to create turbulence in the flow.... [like the valve slamming open and shut 9 zillion times a minute would not..] I could not tell the difference.....
Yep i was thinking the same(urban myth), i am goin to remove them in head runners. Also i will be coating runners with ceramics wich prevent gas sticking to the runner walls.
Well, there is a ton of different ideas,,, but one that makes sense to me is that inside a port or runner a mirror finish is not good,,, a slightly rough finish, and I am talking slightly rough, allows the air stream to ''tear'' the gas vapors from the sides and get them into the air stream as a vapor so the mixture can burn.....at least that is what FoMoCo said....
Wrapping up the DDP mod on my intake and was wondering what would happen if I removed a portion of the plenum divider. I was looking the Gessler's website and noticed he takes a section of the divider out - is this for better flow or clearence for the carburator butterflies? I also noticed he removes alot more material from the manfold; reshaping the opening. Also, I noticed some of the edelbrock manfolds (i.e. RPM air gap) have a lowered divider. Does anyone think making a change to the divider will enhance performance or will I just be changing the RPM of the power band? Thanks Doug
